10.20.11 1:58 AM ET

In one year, a serial killer slaughtered eight women and one man while unleashing a brutal rampage of sexual assaults, robberies, and kidnappings that terrorized Phoenix. He grabbed one victim at a car wash and another at a bus stop. He executed two women in their food truck. He left one corpse in an alley, another in a bathtub.

Dubbed the "Baseline Killer," he prowled the city from the summer of 2005 to the summer of 2006.

Adding to the terror, a separate killing team marauded Phoenix at the same time, fatally shooting six people and injuring more than a dozen others as if they were in a videogame. (Three men were convicted in connection with these "serial shootings," and one of the three was sentenced to death.)

But while the serial shooters tended to shoot victims from a distance, the Baseline Killer wore disguises and stalked women. If they didn't give in to his sexual advances, he shot them in the head. Many victims were Hispanic. A billboard showing a police sketch of the killer—a mustached man with an empty stare, costumed in a long dreadlocks wig and fishing hat—only served to further fray the city's nerves.

Then in September 2006, police arrested Mark Goudeau, a mild-mannered construction worker built like an NFL fullback who had been happily married for more than a decade. His tearful wife, Wendy Carr, painted her husband as a soft-hearted guy who liked to hike and bike with her and take her to the movies. Their marriage, she told Good Morning America, was "idyllic" and "perfect."

But police alleged that Goudeau had brutally sexually assaulted two sisters in a Phoenix park in 2005. Soon after the arrest, detectives found the jewels of one of the Baseline Killer murder victims in Goudeau's closet, the DNA of another victim on his white Nike shoe, and the DNA of still another victim on a ski mask in Goudeau's hamper.

Police pored over ballistics and DNA records, and concluded that Goudeau was the Baseline Killer.

A series of long court trials ensued. In 2007, Goudeau was sentenced in Maricopa County Superior Court to more than 400 years in prison for assaulting the two sisters in 2005. Next, in a trial that began this June, Goudeau pleaded not guilty to 72 counts connected to the Baseline Killer crime spree.

Now that second trial is drawing to an end. Earlier this week, during closing arguments attended by mothers, sisters, sons, and a boyfriend of the Baseline Killer's murder victims, prosecutors painted Goudeau as a "ravenous, careful, cunning wolf." They said his mild manners and nice-guy demeanor were "sheep's clothing" for a "predator" who "hunted" victims. Goudeau killed all the victims with the same gun, wore freaky disguises, executed women who would not submit to sex, and, despite his best efforts to avoid discovery, left DNA evidence behind at the crime scene or took it home, said prosecutor Patricia Stevens.

Goudeau's attorney, Randall Craig, told jurors that multiple suspects probably committed the crimes attributed to the Baseline Killer. The cops nabbed the wrong man, Craig said. He said no murder weapon, fingerprints, hair fiber, footprints, or witnesses could put Goudeau at the crime scenes, and that the DNA evidence was suspect. He suggested the jewels had been planted in Goudeau's shoe.

"They never found the guy," Craig insisted.

On Wednesday, the jury began deliberations. If convicted of any murder, Goudeau, 47, could be sentenced to death.

Goudeau's wife, Wendy Carr, could not attend the trial because she is a potential witness should the case go into a death-penalty phase. But she still maintains her husband's innocence, and suggests that the police and prosecutors wrongly arrested him for political and racial reasons. (Goudeau is black; his wife implies the police are racist.) Carr blogs energetically in her husband's defense. In one post, she writes that she would have known if he had been on a crime rampage, but "there was nothing odd or peculiar that I saw." She portrays herself and Goudeau as "just a couple of regular people who loved each other’s company, enjoying even the smallest things of life." He was, she reports, a loyal, considerate husband who cried when they put their dog down, made chili-dog dinners, and puttered in the garden.

But court records paint a different portrait.

Paul Connors / AP Photo

Wendy Carr, the wife of Mark Goudeau, at a press conference in 2006, after he was charged in connection with a sexual-assault case

Goudeau was born in Phoenix to a poor family. A high-school dropout, he frequented nightclubs and told people he was a former NFL player or an architect, records say. In truth, he toiled at low-paying jobs for years at a time. He worked on an assembly line, drove a water-delivery truck, and managed a crew for Budget Car Sales.

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In 1982, court records say, one woman told police that Goudeau and his close relative raped her. She did not press charges.

A few years later, Goudeau met Carr, a slender woman with a mane of long reddish-brown hair, at a Phoenix nightclub. They began their relationship.

While he was involved with Carr, police found a bloodied, half-conscious woman by his Datsun. Witnesses had called police because they had seen a man beating the woman with a shotgun in a parking lot.

The woman named Goudeau as her attacker from her hospital bed. She said she'd met him in a club, they'd hooked up, and he later bashed her head with a barbell, threw her in a bathtub, and tried to drown her.

She thought she was "in a room with the devil," according to court records. Goudeau, then 25, denied bludgeoning or otherwise hurting the woman, and claimed she made sexual advances toward him.

While on bond for the assault charges, Goudeau robbed a grocery store. He served 13 years in prison for burglary, kidnapping, and aggravated assault. Wendy Carr stood by him and married him in prison.

After his 2004 prison release, he worked at a construction company. A parole officer reported that Goudeau was "cooperative and polite," but Carr was "a little aggressive," according to court documents.

The Baseline Killer began his rampage in 2005, after Goudeau was released from prison.

Before he received his more than 400-year sentence for the 2005 sexual assault of the sisters in the city park, a Phoenix Police detective reported in court records that Goudeau had "demonstrated violence" in every past relationship "except in his current marriage."

Wendy Carr's sister, Debbie, says her sister still believes her husband is innocent. Debbie, like Wendy, maintains Goudeau is a "political prisoner," wrongfully charged. Evidence was planted, Debbie told me, because elected officials had to "do something" to ease the city's anxiety over the serial killer on its streets. The real Baseline Killer had been discovered by a police detective but was never charged with the crime, Debbie suggested.

Wendy Carr sought an explanation for her misfortune from a psychic, Debbie said. The psychic, Debbie reported, could offer no explanation, other than to say Wendy's relationship with Goudeau was steeped in bad blood.

If the Phoenix jury that is now deliberating finds Goudeau guilty of even one of the serial killings, it is likely that Carr will testify on her husband's behalf in an effort to spare him the death penalty. She'll finally have her day in court.

Mary Shinn, a student reporter at the Walter Cronkite School of Journalism and Mass Communication at Arizona State University, contributed to this report.